The scope of the present invention is that of projectiles designed to attack hard constructions of the type comprising structures made of, for example, stone, brick, cement or other building materials.
Such targets are usually reserved for engineering teams who are entrusted with the task of placing explosives directly onto the construction.
However, from a tactical point of view, such operations are difficult to perform.
Research has been undertaken in order to design projectiles that may be fired from a safe distance and are able to cause significant damage to such targets.
However, the targets are, more often than not, protected by a substantially deep layer of sand bags that cause the initiation of common explosive charges at a distance from the stone or cement construction that is too great for any great damage to be caused to the construction.
Projectiles having devices for distinguishing targets according to their hardness are known elsewhere.
Patent EP433254 thus describes a projectile having a double contactor in the nose cone. A first contact is closed during the impact on a "soft" target, such as an aircraft or light vehicle. The first contact causes the charge to be initiated after a certain delay, that is to say when the projectile finds itself more or less inside the target.
A second contact is closed during the impact on a "hard" target, that is to say a target that the projectile can not pierce. The second contact causes the instant initiation of the explosive charge.
Such a projectile is able to tell the difference between a "soft" target such as a light vehicle or an aircraft and a "hard" target such as a tank, but it remains ineffective against targets of the building or extra-protected "hot" caves.
In fact, the hardness of impact on extra-protections such as sand bags causes the instant initiation of the charge at a distance from the building construction that is too great to cause the building any damage.